The present invention relates to a waterproof lens-fitted photo film unit that contains a body of the lens-fitted photo film unit in a watertight waterproof case to permit photographing in the water, and relates also to an assembling method therefor. More specifically, the present invention relates to a waterproof lens-fitted photo film unit that is superior in waterproof properties and handing properties, saves manufacturing cost, prevents mishandling thereof and prevents defective joints in the waterproof case, and also relates to an assembling method therefor.
Lens-fitted photo film units, which are preloaded with a photo filmstrip and provided with simple photographic mechanisms, are widely used in the world because of its handiness. There are a variety of lens-fitted photo film units for use in different photographic purposes and applications. For example, there are a flash type that allows photography even in the night, and a non-flash type which is simplified by minimizing functions to essential ones. There is also a waterproof lens-fitted photo film unit that permits photography in the water as a body of the lens-fitted photo film unit, hereinafter referred to as the film unit body, is contained in a waterproof case that has a watertight structure.
Of the waterproof lens-fitted photo film unit, operation members are provided on the waterproof case, such that actuation members may be operated from outside the waterproof case, wherein the actuation members are provided in the film unit body for actuating a flash device, a shutter mechanism or the like. These operation members of the waterproof type are made comparatively larger than actuation members, such as a shutter button, of other types of lens-fitted photo film units, or they are protruded from external surfaces of the waterproof case, so that the operation members may be operated without fail even in the water or when the photographer wares thick gloves.
An example of these operation members is an operation button made of rubber, as disclosed in Japanese Patent Application No. 9-347754. This operation button is attached to the waterproof case by force-fitting a portion of the button into a hole that is formed in the waterproof case, from outside the waterproof case, and can be pressed for operation because of its resiliency. In this way, waterproof property is obtained. Because being supported by the external surface of the waterproof case, this operation button is proof against the pressing operation from outside to inside, pressures from water and the like.
As the operation button is formed as an integral part from rubber, it is superior in water-tightness, and also reduces the number of parts and the cost for manufacturing and assembling the waterproof case. However, since the operation button is mounted from the outside, it is easy to remove, so the case is likely to loose its water-tightness. Where the operation button is protruded outward from the waterproof case, it can be pressed unexpectedly while the lens-fitted photo film unit is carried in a bag, or in other situations like that.
The lens-fitted photo film unit contains a photo film cartridge with its unexposed photo filmstrip previously pulled out from a cartridge shell and coiled into a roll. A winding knob that is coupled to a spool of the cartridge shell is rotated after each exposure, to wind up the photo filmstrip by each exposed frame into the cartridge shell. A shutter mechanism is designed to be charged in cooperation with the winding knob being rotated for winding up one frame. For this purpose, the film unit body is provided with a stop-winding mechanism for locking the winding knob from rotating when one frame of the photo filmstrip has been wound up into the cartridge shell. The stop-winding mechanism cooperates with the movement of the photo filmstrip, and includes a stop lever. The stop lever is brought into engagement with teeth that are formed around an external periphery of the winding knob when the winding knob is rotated in a winding direction by an amount corresponding to one frame. Besides, an anti-reverse claw is provided on the film unit body. The anti-reverse claw is engaged with the teeth around the winding knob, for preventing the winding knob from being rotated in reverse to the winding direction.
In the waterproof lens-fitted photo film unit, a winding dial is provided on the waterproof case, and is engaged with the winding knob of the film unit body. The winding dial is made larger in diameter than the winding knob, thereby to obtain a larger rotational torque, and thus improve handling properties thereof, as it is operated in the water or with gloved hands. For this reason, the anti-reverse claw provided for the winding knob is too weak to securely prevent reverse rotation of the winding dial.
Japanese Laid-open Patent Application No. 5-248448 discloses a teaching to provide a torque limiter between the winding knob of the film unit body and the winding dial on the waterproof case, such that the torque limiter does not transmit rotational force from the winding dial to the winding knob if the winding dial is rotated while a load is applied to the winding knob or while the winding knob is locked. Because of this torque limiter, if the winding dial is rotated in the winding direction or in the reverse direction while the winding knob is locked, the winding dial idles, and the winding knob does not rotate.
However, because the torque limiter as above allows the winding dial to rotate endlessly, if the user does not know much about this type of waterproof lens-fitted photo film unit, the user might not notice that the winding knob is being rotated reversely, and could not take photographs.
The film unit body is generally constituted of a body base portion in which the photo filmstrip is loaded and the photographic mechanisms, including the shutter mechanism, are incorporated, and front and rear covers that covers front and rear sides of the body basic portion. These parts are modified according to the type of the lens-fitted photo film unit. For instance, the body base portion for the flash type is provided with a mounting portion for a flash unit that is constituted of a capacitor, a battery, a circuit board and so forth. The front cover for the flash type is provided with a flash opening for exposing a flash projector. On the other hand, in the non-flash type, the flash unit mounting portion and the opening for the flash projector are not provided, thereby to eliminate useless spaces and useless parts.
In order to use specific parts for the respective types of lens-fitted photo film unit, metal molds are needed for forming the specific parts of the respective types. This has been one of causes of raising manufacturing cost of the lens-fitted photo film unit. As for the waterproof lens-fitted photo film unit, not only the film unit body but also the waterproof case need to be modified depending upon whether it is with flash or without flash, so the increase in the manufacturing cost is more remarkable.
When assembling the waterproof lens-fitted photo film unit, it is conventional to mount the operation members to the waterproof case water-tightly before inserting the film unit body in the waterproof case and joining a pair of members that constitute the waterproof case to each other in a watertight fashion.
However, when the pair of case members are water-tightly joined to each other after the operation members are mounted water-tightly, air cannot get out of the waterproof case, and is confined in the waterproof case in a compressed condition, so the air pressure inside the waterproof case gets higher. As a result, a load is applied to joints between the case members, and sometimes breaks or loosens the joints, so the case looses its water-tightness. For the same reason, defective products with incompletely joined case members are likely to be manufactured.
The present invention is made to solve the above problems, and has an object to provide a waterproof camera or a waterproof lens-fitted photo film unit with an operation button that is proof against the pressing operation and water pressure, and is not easy to remove. The present invention also has an object to provide a device for preventing the operation button from being wrongly operated.
Another object of the present invention is to provide a waterproof lens-fitted photo film unit that makes it possible to carry out film winding operation without fail while preventing reverse rotation of the winding dial.
A further object of the present invention is to make it possible to manufacture a non-flash type waterproof lens-fitted photo film unit at a low cost.
Still another object of the present invention is to provide a waterproof lens-fitted photo film unit that can be assembled efficiently in a watertight fashion, while preventing breakage and defects in joints between case members, and an assembling method therefor.
A waterproof camera of the present invention is characterized by comprising a camera body having an actuation member that actuates an internal mechanism when the actuation member is pressed; a waterproof case that contains the camera body in a watertight fashion, the waterproof case being provided with an opening in a position facing the actuation member and a stepped portion around the opening on an inside wall of the waterproof case; an operation member having a button portion exposed to outside through the opening and a mounting portion fitted on the stepped portion, the operation member being formed as an integral part from a resilient material and resiliently deformed to press the actuation member when the button portion is pushed in; and a supporting member that pushes the mounting portion against the stepped portion from inside of the waterproof case, thereby to secure the operation member. The waterproof camera of the present invention includes a waterproof lens-fitted photo film unit that is preloaded with a photo filmstrip while it is manufactured. The above camera body includes a film unit body.
Because the operation button is constituted of the button portion and the mounting portion, and the button portion is fitted in the opening of the waterproof case from inside and is exposed to the outside of the waterproof case, whereas the mounting portion is force-fitted in the stepped portion that is formed around the opening on the inner wall of the waterproof case, and also because the operation member is secured by pressing the mounting portion against the inner wall of the waterproof case by means of the supporting member, the operation member is proof against the pressing operation and the water pressure, and is uneasy to remove from outside the waterproof case. Forming the supporting member integrally on the outer surface of the camera body contributes to reducing the number of parts and the number of assembling processes, and also provides a stable support. By making the button portion protrude out of the waterproof case, and forming an outward protrusion on the edge of the opening to surround the button portion at least partly, the operation member is prevented from being pressed unexpectedly.
According to another aspect of the present invention, in a waterproof lens-fitted photo film unit that comprises a film unit body having a photo filmstrip preloaded therein and a waterproof case that contains the film unit body in a watertight fashion, wherein the film unit body is provided with a taking lens, photographic mechanisms, a winding knob rotated for winding up the photo filmstrip after each exposure of one frame, a stop-winding mechanism for locking the winding knob when the photo filmstrip has been wound up by one frame, and an anti-reverse device for preventing the winding knob from rotating in a direction reverse to a film winding direction, whereas a winding operation member for rotating the winding knob from outside of the waterproof case is pivotally mounted on the waterproof case, the waterproof lens-fitted photo film unit is characterized by comprising a torque limiter that normally couples the winding operation member to the winding knob, and releases the winding operation member from the winding knob when the winding operation member is rotated while the winding knob is locked by the stop-winding mechanism, or when the winding operation member is rotated in the reverse direction; and a second anti-reverse device for stopping the winding operation device from rotating in the reverse direction.
Even if the winding operation member is operated to rotate in the reverse direction, the second anti-reverse device stops the winding operation member from rotating reversely, so the user will notice that the winding operation member is being rotated reversely. If the winding operation member is rotated while the winding knob is locked by the stop-winding mechanism, the torque limiter disengages the winding operation member from the winding knob, so the winding operation member idles, and the stop-winding mechanism or the photo filmstrip would not be broken. Even if the winding operation member is forcibly rotated in the reverse direction to break the second anti-reverse device, because the anti-reverse device for the winding knob applies a load on the winding knob when the winding operation member is being further rotated reversely, the torque limiter releases the engagement between the winding operation member and the winding knob, so the winding operation member idles. In this way, the winding knob is securely prevented from being rotated reversely.
According to a further aspect of the present invention, in a waterproof lens-fitted photo film unit comprising a non-flash type film unit body that does not have a flash device mounted therein, and a waterproof case that is at least partly transparent and contains the film unit body in a watertight fashion such that the film unit body may be operated from outside the waterproof case, wherein the film unit body comprises a body base portion containing a photo filmstrip and having a taking lens and photographic mechanisms mounted therein, and front and rear covers covering the body base portion from front and rear sides thereof, the waterproof lens-fitted photo film unit is characterized in that the body base portion and the front cover are designed for a flash-type film unit body that is to have a flash device mounted therein, and the front cover is formed with a flash opening for exposing a light projecting portion of the flash device; and that a shielding device for shielding sight of the flash opening from outside the waterproof case is provided.
According to a method of the present invention for assembling a waterproof lens-fitted photo film unit, wherein a non-flash type film unit body having no flash device mounted therein is contained water-tightly in an at least partly transparent waterproof case such that the film unit body may be operated from outside the waterproof case, a taking lens and photographic mechanisms are mounted to a body base portion that is provided with a mounting portion for a flash device, without mounting the flash device; a photo filmstrip is loaded in the body base portion; the front of the body base portion is covered with a front cover that has a flash opening for exposing a light projecting portion of the flash device; and a shielding device is provided for shielding sight of the flash opening from outside the waterproof case.
Since the non-flash type film unit body uses the front cover that is formed with the flash opening for exposing the light projecting portion of the flash device, and the shielding device for shielding sight of the flash opening from outside the waterproof case is provided, it becomes possible to use common parts to the flash type unit body, so the non-flash type waterproof lens-fitted photo film unit may be manufactured at a low cost. As the parts that constitute the non-flash type unit body are equal in shape and size to those used for the flash type unit body, it is possible to produce the waterproof case for the non-flash type just by applying a little modification to a flash type waterproof case. Therefore, the cost of manufacture is still more reduced.
According to another assembling method of a waterproof lens-fitted photo film unit of the present invention, the whole film unit body is covered with a pair of case members that constitute a waterproof case, and these case members are joined to each other in a watertight fashion, and thereafter an operation member, such as at least one of those members for operating a shutter mechanism, a film winding mechanism and a flash device, is coupled to the waterproof case in a watertight fashion. When the case members are water-tightly joined together, the air inside the waterproof case escapes through an opening for mounting the operation member, so the air pressure inside the waterproof case is not increased.
By providing at least one of a pair of case members that constitute a waterproof case, with a pressure regulating device for equalizing the internal air pressure inside the waterproof case to atmospheric pressure when said case members are joined to each other, the air pressure inside the waterproof case would not be increased even when the pair of case members are joined together in a watertight fashion after the operation members are water-tightly mounted to designated positions of the pair of case members.